Earthquake Recovery Minister Gerry Brownlee says he is ''staggered'' by a Christchurch City Council resolution to consider, on a case-by-case basis, funding rockfall protection work on red-zoned Port Hills properties.

''This has blindsided us. We didn't see it coming,'' Brownlee said.

Under a resolution passed by councillors today, red-zoned home-owners wanting to stay in their homes could be given up to half the 2007 capital value of their property to spend on building and maintaining rockfall protection such as fences and bunds.

To take up the offer, they will have to convince the council the proposed work complies with the council's technical design standards and is financially feasible.

If they want to build the rockfall protection on council land they will also have to prove it will not impede on the use of the land for its intended public purpose or detract from its amenity value.

Brownlee said this afternoon the decision by councillors was ''extremely disappointing''.

He said the council was involved in making the decision to red-zone the Port Hills properties on an area-wide basis, with both Mayor Bob Parker and chief executive Tony Marryatt present at the ''collegial'' discussions.

''I'm pretty staggered,'' he said.

''It's a reversal of the council's position. They were very much party to the decision on the rock-roll properties. This decision today undoes it. It's tragic for many people who will get caught up in it who don't want to.''

''We've been through so much discussion on this and tried to be as clear and fair as we possibly can. This just completely puts us right back to the start.''

He said the Government would not consider re-zoning properties where rock protection work was carried out.

Brownlee said he would assess what the resolution may mean over the weekend.

He would also take advice and talk to colleagues next week on whether ''we should be progressing the Government-offer process''.

Brownlee said the first he had heard of the council's resolution was in media reports and he hoped someone from the council would phone and tell them the "deal".

Cr Tim Carter said considering rockfall protection measures for individual properties on a case-by-case basis made "financial prudent sense'' as it could potentially save ratepayers money.

"I can't see any reason why everyone at this table would not support this,'' Carter said.

Under an agreement reached with the Crown earlier this year the council has already committed to spend $57.9 million on buying out homes that have been red-zoned because of the rockfall risk.

It has the discretion though to spend some of that money on rockfall protection work if it believes it would be more cost-effective.

Cr Aaron Keown said he was extremely proud the council was taking steps to help people stay in their homes: "For a small number of people this will change their lives immensely.''

Cr Sue Wells said she was happy to support the initiative but did not want to give people false hope or raise expectations as the process of getting council approval for rockfall protection work would not be easy.

Mayor Bob Parker said a "doorway had opened'' for some red-zoned Port Hills residents but warned the number of property owners likely to satisfy the council's criteria for funding would be small.

The motion to consider providing council funding for rockfall protection work on a case-by-case basis was supported unanimously - and greeted with applause by Port Hills residents who had sat in the gallery throughout the debate.

Some cried, others hugged as the news of the decision sunk in.

Speaking outside the meeting resident Phil Elmey, who had repeatedly lobbied the council for help, said the council's decision came as a huge relief.

"There's still work to be done but it is very significant decision,'' Elmey said.

Council staff had recommended against the council contributing any funding towards the cost of private rockfall mitigation.